vocd: A theoretical and empirical evaluation

A reliable index of lexical diversity (LD) has remained stubbornly elusive for over 60 years. Meanwhile, researchers in fields as varied as stylistics, neuropathology, language acquisition, and even forensics continue to use flawed LD indices — often ignorant that their results are questionable and in some cases potentially dangerous. Recently, an LD measurement instrument known as vocd has become the virtual tool of the LD trade. In this paper,...